This invention relates to the art of fluid flow piping systems and, more particularly, to adapter fittings for use in such systems.
Fluid flow components of the type which can be bolted together and provide sealing at mating faces offer many advantages over conventional piping and control systems. These advantages include sealing integrity, a minimum number of joints, and compact overall dimensions. Fluid flow components of the indicated type can be used at any outlet that has a bolt-on flange configuration. However, it would be desirable to be able to adapt the fluid flow components of the indicated type for use with many types of outlets, in addition to the bolt-on flange configuration, since this should increase the number of applications that can benefit from the advantages thereof. In particular, it would be desirable to be able to use these fluid flow components with positive sealing type thread connections such as the SAE straight-thread connections.
In high pressure flow applications, it is important that the flow be contained without failures or leakage and the system be assembled easily and efficiently maintained. The hydraulic industry in the United States has promoted the SAE Straight Thread Standard J1926 and the SAE 4-Bolt Split Flange Standard J518 as the ports that best meet these critera. In my copending application Ser. No. 776,497 filed Sept. 16, 1985, now U.S. Pat. No. 4,889,369 it is taught how to effectively adapt a thread to a flange and there is disclosed an adapter fitting which enables fluid flow components of the indicated type to be used with various types of outlets including the positive sealing threaded connections and bolt-on flange connections. The present invention is another form of adapter fitting of the type disclosed in said copending application.
The SAE standard four bolt port is designed for use with a flange construction using four bolts arranged in a generally rectangular bolt pattern and to accommodate a flange system that employs a split flange arrangement as described in said SAE J518 specification. In accordance with my prior invention, it is shown that the adapter fitting can be designed effectively using a four bolt flange geometry as a solid flange.
Most of the flanges in the SAE four bolt split flange systems are rated at relatively high pressures, such as 3,000, 5,000 and 6,000 PSI. However, because of their high acceptance in the industry, many of these flanges are used on components with pressure ratings significantly below the maximum rating of the SAE J518 specification. For example, this port configuration is used on pump suction lines that may see only low positive pressure and/or small amounts of subatmospheric pressure. Also, many components have these ports on tank to reservoir lines with pressures that are normally much lower than the pressure rating of these ports.
In accordance with the present invention there is disclosed an alternate flange construction for use in adapter fittings of the indicated type that can be effectively employed at a reduced pressure rating, such as at pressures up to half or less than the maximum high pressure rating. Briefly stated, the flange system in accordance with the present invention employs only two bolting connections in the flange construction. The design permits a virtually leakproof connection to the four bolt pattern by connecting to either of the diagonal bolt holes in said bolt pattern. Furthermore, the flange design in accordance with the invention facilitates faster assembly as a lower pressure union connector since it only requires the assembly of two bolts. Further, the flange design in accordance with the invention conserves material and labor on new component designs since only two tapped holes are required on the component and these holes are located on the center line with the fluid port. In addition, the design greatly maximizes the flexibility on lower pressure piping while reducing time, material and cost.